<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        img {
            width: 300px;
        }
    </style>
</head>
<body>
    <button id="ldh">刘德华</button>
    <button id="zxy">张学友</button><br>
    <img src = "images/ldh.jpg" alt="" title="ldh">
    <script>
        //修改元素属性  src
        //1.获取元素
        var ldh = document.getElementById('ldh');
        var zxy = document.getElementById('zxy');
        var img = document.querySelector('img');
        //2.注册事件 处理程序
        zxy.onclick = function () {
            img.src = '../images/zxy.jpg';
            // img.title ='zxy你为什么那么出名';
        }
        ldh.onclick = function () {
            img.src = '../images/ldh.jpg';
            // img.title = '在你成名前是不是也经历过很多挫折时刻呢';
        }
    </script>
</body>
</html>